Mist sensor

ABSTRACT

A mist sensor for sensing mist such as oil mist used for lubricating purposes so as to give a warning if the oil mist falls below a predetermined density so that the machine being lubricated may be stopped before being damaged. A test circuit and indicator is provided for assuring that the warning light is operative so that the indicator will not fail to operate due to a faulty indicator circuit.

United States Patent Ronald F. Obergetell lnventors Cleveland;

Robert R. Roberts, Streetsboro, both of, Ohio Appl. No. 757,401 FiledSept. 4, 1968 Patented June 22, 1971 Assignee l-loudaile Industries,Inc.

' Cleveland, Ohio MIST SENSOR 4 Claims, 3 Drawing Figs.

U.S. Cl 340/270, 250/2 I 8 int. Cl G081: 21/00 Field ,olSearch 340/235,236,237,270; 250/218 [56] References Cited UNITED STATES PATENTS2,935,909 5/1960 Mathisen 250/218 UX 3,268,734 8/1966 Bjorn 250/2183,417,250 12/1968 Kadivnik 250/218 3,469,250 9/1969 Voigt 340/237Primary Examiner-Robert L. Richardson Attorney-Hill, Sherman, Meroni,Gross & Simpson ABSTRACT: A mist sensor for sensing mist such as oilmist used for lubricating purposes so as to give a warning if the oilmist falls below a predetermined density so that the machine beinglubricated may be stopped before being damaged. A test circuit andindicator is provided for assuring that the warning light is operativeso that the indicator will not fail to operate due to a faulty indicatorcircuit.

PATENTEH JUN22 12m sum 1 or 2 PATENTED JUH22|97| SHEET 2 BF 2INVIiN'IORS Row/2w F amserzzz. 05627 0. Koaaers M and V MIST SENSORBACKGROUND OF THE INVENTION l. Field ofthe Invention This inventionrelates in general to lubricating means and in particular to an oil-mistsensor which detects the density of oil mist or other mist and which isa warning indicator when the density of the mist falls below apredetermined level.

2. Description of the Prior Art Prior art systems have used oil-mistlubrications which mix high velocity air and oil to generate a finespray. The fine spray is provided by suitable conduit means to parts,such as bearings, that are to be lubricated.

SUMMARY OF THE INVENTION The present invention relates to a sensingdevice which indicates when the density of oil or other mist falls belowa predetermined level. When this occurs, a photoelectric cell energizesa warning circuit which indicates that a danger condition exists. So asto assure that the warning indicator is operative, a bulb filamentdetection circuit is provided which monitors the condition of thewarning bulb has opened. Thus, the circuit provides an oil-mistmonitoring device and a circuit for assuring that the warning device isoperative.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of certainpreferred embodiments thereof taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top'view which has beenpartially cut away to show the oil-mist sensor of this invention;

FIG. 2 is a sectional view taken on line Il-Il of FIG. I; and

FIG. 3 is a schematic view of the oil-mist sensor according to thisinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. l and 2 illustrate theoil-mist sensor of this invention. The sensor is mounted in a conduitwhich has an input I8 that is connected to one end of the sensor 10 andan output conduit 19 which is connected to the other end of the sensor110. A sideplate ll of the sensor 10 is formed with brackets 12 and 113for mounting the sensor on a suitable support means, (not shown). Thesensor 10 has a hollow chamber through which the oil mist passes and isformed with a top wall 14 and a bottom wall 17. A photoelectric cell 21is mounted in one end of the sensor above the conduit 19 and has atransluscent protective cover 22. The photocell is mounted by suitablemounting bolts 23, as shown in FIG. I. A protective conduit 26 isconnected by a coupling 27 to the photocell support and has its otherend connected by a coupling 31 to a light support 29 in which a lightbulb 28 is mounted. Suitable electrical conductors 32 are connected tothe light bulb and photocell 21.

FIG. 3 is the electrical schematic for the mist sensor and bulb failuredetection circuit. A power plug 33 has a grounded plug and two powerleads 36 and 35. An on-off switch S is connected in lead 35 and connectslead 35 to lead 34 when the switch S is closed. The primary 37 of atransformer T is connected across the leads 34 and 36. The secondary 38of the transformer T has one side connected toa diode D which is poledin a first direction, and to a second diode D, which is poled in theopposite direction. The other side of the secondary 33 is connected toground. A first capacitor C to ground, and a second capacitorC isconnected from the other side of the diode D to ground. A diode D hasone side connected to lead 39 and the other side connected to an SCRwhich has its other side connected to a resistor R which has its otherside grounded. The gate 50 of the SCR is connected to a capacitor Cwhich has its opposite side grounded and to the wiper contact 55 of apotentiometer R One end of the potentiometer R is connected to aresistor R, which has its other side connected to the junction pointbetween the diode D and the capacitor C A reset switch S and relay R areconnected in series across the diode D;,. A resistor R and the photocell21 are connected in series between the diode D and the gate 50 of theSCR.

A normal operating light L is connectedacross the leads 34 and 36 inseries with switches SR and SR which are normally closed when the oilmist is above a predetermined density and the bulb 28 is operating. Alow density warning light L ssonnsstsdfssmtW le 4.20 a m y Open SwitchSR1 v which has its other side co nnectedto the le am.Aiinkage 46 s nn sithsswitshcsl II nQSJiw. $YLl R u l!l. 5311' are connected by link 44and are controlled by the relay R5,.

The primary 42 of a transformer T is connected to the leads 34 and 36. Asecondary 43 of the transformer T has a first side which is connected tooppositely poled diodes D and D and condensers C and C, are connectedacross the other sides of the diode D and D The junction point betweenthe capacitors C and C is connected to the other end of the secondary43. A resistor R is connected from the diode D to the light 28 which hasits other side connected to the diode D A resistor R and a relay R andreset switch S;, are connected in series across the light 28.

The power supplied to the plug 33 is normally 1 15 volts, 60 cycle andthe transformer T converts the AC to 20 volts AC. The diodes D, and D,convert the AC to DC and the capacitors C, and C filter the powersupply.

The photocell 21 and potentiometer comprising the resistor R and contact55 from a voltage dividing circuit with one side of the photocellconnected to the positive side of the power supply through the resistorR and one side of the potentiometer connected to the negative side ofthe power supply through the resistor R The junction points of thepotentiometer and photocell are connected to the gate 50 of the siliconcontrolled rectifier, SCR. The silicon controlled rectifier requires a+0.8 volts to trigger it intoa conducting state, and when the siliconcontrolled rectifier conducts, it energizes the relay R If theresistance of the photocell drops due to a high light intensity beingreceived from the bulb 28, which indicates that the oil-mist density islow, the gate 50 will reach 0.8 volts and the SCR will be turned on.

The gating level of the SCR will depend upon the setting of the contact55 of the potentiometer R The lower the resistance set across thepotentiometer, the more negative the gate of the SCR becomes, and sincethe SCR will not trigger on negative voltage, the photocell must thendrop even lower in resistance to make the gate positive. Thus, theadjustment of the potentiometer contact 55 determines how low theresistance of the photocell must be before triggering occurs. Thecontact 55 therefore adjusts the light level setting (and thus thedensity) at which triggering of the-SCR occurs.

The transformer T, converts the volt, 60 cycle to 20 volt AC which isrectified and filtered by the diodes D D and capacitors C and C Thelight 28 and resistor R are connected in series across the rectifiedpower supply and the light 28 will glow if the bulb filament is good.The filament of the bulb 28 is in parallel with the resistor R and relayR and the relay will remain unenergized as long as the filament in thebulb 28 is intact. If the filament in the bulb 28 opens, the currentthrough the relay R will become large enough to cause it to pull in andmove the linkage 44 closing the switch SR and opening switch SR Thereset buttons 5: and S; allow the circuits to be reset.

Thus, in operation, with a suitable density of oil mist passing throughthe sensor 10, the resistance across the photocell 21 will besufficiently high to prevent the SCR from being gated on. Under theseconditions, the relay R will be unenergized and the switches SR SRn'willbe in the position shown in FIG. 3. lfthe filament ofthe light 28 isgood, the relay R will be unenergized and the switches SR and Sli willbe in the position shown in FIG. 3. If the density of the oil mistdecreases to a point where the light received by the photocell 21 fromthe light 28 is sufficient to reduce its resistance to the gating pointof the SCR, relay R will be energized and switch SR will open turningoff the normal operation light L and switchSR will close turning on thelow mist density warning light L The operator will note the warninglight and will correct the condition to increase the oil density or takeother necessary action.

In the event that the filament in the light 28 fails, the relay R willbe energized. thus opening the switch contact SR, and closing switchcontact SR This will turn off the normal operation light L, and turn onthe bulb-failure warning light L The operator will then replace thelight bulb 28 and push the reset button S Although minor modificationsmight be suggested by those versed in the art, it should be understoodthat we wish to embody within the scope of the patent warranted hereonall such modifications as reasonably and properly come within the scopeof our contribution to the art.

We claim:

1. Apparatus for detecting the density of a fluid comprising:

a chamber through which said fluid passes,

a light source having a filament for supplying light in said chamber,

a light detector mounted to receive light from said light source,

a power supply,

a first relay,

a silicon controlled rectifier connected in series with said first relayacross said power supply,

the light detector connected to one side of the power supply and to thegate of the silicon controlled rectifier,

a second relay connected in parallel with the filament of said lightsource and energized when said filament is open,

three indicators,

a first pair of switches in series with a first of said indicatorsacross said power supply,

a third switch connected in series with a second of said indicatorsacross said power supply,

a fourth switch connected in series with a third of said indicatorsacross said power supply,

said first relay connected to control the first one of said pair ofswitches and the third switch such that when one is open the other isclosed, and

said second relay connected to control the second one of said pair ofswitches and the fourth switch such that when one is open the other isclosed.

2. Apparatus according to claim 1 comprising a potentiometer connectedin circuit with the light detector and the gate to adjust the gatinglevel of the silicon controlled rectifier.

3. Apparatus according to claim 1 comprising a second impedance incircuit with said second relay.

4. Apparatus for detecting the density of a fluid according to claim Iwherein said first pair of switches are closed when the density of fluidin the chamber is sufficient and the first indicator is activated,

wherein said third switch is closed and the first one of said pair ofswitches is open and the second indicator is activated when the densityof fluid in said chamber is below a desired level,

and wherein said fourth switch is closed and the second of said pair ofswitches is open and the third indicator is activated when the filamentis open.

s, 587, 079 Dated June22, 1971 Patent No.

RONALD P. OBERGEFELL and ROBERT D. ROBERTS Inventor(s) It is certifiedthat error appears in the. above-identified patent and that said LettersPatent are hereby correc ted as shown below:

Title Page [73] Aslsignee:"i-ioudei1e" should read -Houdaille Title Page{72] inventors: "Robert Rm Roberts" should read -Robert DO Roherie nColumn. 1, line 25, after huib insert "and indicates when the filamentof ihe Warning bulb;

line 68 after "C insert "is connected from the other side of the diode13.

Column 2, line (as, "SE should. read -SR Simoed and sealed this 28th dayof March 1 972.

(SEAL) Attest:

ROBERT GOTTSGHALK EDWARD MnFLLElTGHER, 5H

Commissioner of Patents Attesting Officer FORM PO-iDSO (10-69) USCOMM DC60376 was S GOVERNMENT PRlNHNG OFFICE $969 0-36633

1. Apparatus for detecting the density of a fluid comprising: a chamberthrough which said fluid passes, a light source having a filament forsupplying light in said chamber, a light detector mounted to receivelight from said light source, a power supply, a first relay, a siliconcontrolled rectifier connected in series with said first relay acrosssaid power supply, the light detector connected to one side of the powersupply and to the gate of the silicon controlled rectifier, a secondrelay connected in parallel with the filament of said light source andenergized when said filament is open, three indicators, a first pair ofswitches in series with a first of said indicators across said poWersupply, a third switch connected in series with a second of saidindicators across said power supply, a fourth switch connected in serieswith a third of said indicators across said power supply, said firstrelay connected to control the first one of said pair of switches andthe third switch such that when one is open the other is closed, andsaid second relay connected to control the second one of said pair ofswitches and the fourth switch such that when one is open the other isclosed.
 2. Apparatus according to claim 1 comprising a potentiometerconnected in circuit with the light detector and the gate to adjust thegating level of the silicon controlled rectifier.
 3. Apparatus accordingto claim 1 comprising a second impedance in circuit with said secondrelay.
 4. Apparatus for detecting the density of a fluid according toclaim 1 wherein said first pair of switches are closed when the densityof fluid in the chamber is sufficient and the first indicator isactivated, wherein said third switch is closed and the first one of saidpair of switches is open and the second indicator is activated when thedensity of fluid in said chamber is below a desired level, and whereinsaid fourth switch is closed and the second of said pair of switches isopen and the third indicator is activated when the filament is open.